Packaging containers of the single use disposable type for liquid foods are often produced from a packaging material based on paperboard or carton. One such commonly occurring packaging container is marketed under the trademark Tetra Brik® Aseptic and is principally employed for aseptic packaging of liquid foods such as milk, fruit juices etc, marketed and sold for long term ambient storage. The packaging material in this known packaging container is typically a laminate comprising a bulk layer of paper or paperboard and outer, liquid-tight layers of thermoplastics. In order to render the packaging container gas-tight, in particular oxygen gas-tight, for example for the purpose of aseptic packaging such as packaging of milk or fruit juice, the laminate in these packaging containers normally comprises at least one additional such gas barrier layer, most commonly an aluminium foil.
On the inside of the laminate, i.e. the side intended to face the filled food contents of a container produced from the laminate, there is an innermost layer, applied onto the aluminium foil, which innermost, inside layer may be composed of one or several part layers, comprising heat-sealable adhesive polymers and/or heat-sealable polyolefins. Also on the outside of the paper or paperboard bulk layer, there is an outermost heat-sealable polymer layer (decor layer). The heat-sealable polymer layers are often based on low density polyethylene or blends thereof.
The packaging containers are generally produced by means of modern, high-speed packaging machines of the type that continuously form, fill and seal packages from a web or from prefabricated blanks of packaging material, e.g. Tetra Brik® Aseptic-type packaging machines. Packaging containers may thus be produced by the so-called form-fill-seal technology basically including continuous reforming a web of the laminated packaging material by means of a filling machine which forms, fills and seals the web into packages.
An aspect of the Tetra Brik®-type packaging method is, as stated above, the possibility of continuous high-speed packaging, which has considerable impact on cost efficiency. Typically many thousands of packages may be prepared per hour. For example the Tetra Pak® A3/speed may manufacture about 15 000 packages per hour (family-size packaging containers of 0.9 liters and above), and about 24 000 packaging containers per hour (portion packages).
Commonly the packaging container have an opening device in order to facilitate consumer opening, many different types of opening devices including pull-tabs or moulded opening devices, as for example discussed in WO03/095199 and WO/2009/000927.
Objects
One object is to manufacture a packaging material and packaging containers for liquid and semi-liquid food manufactured from the packaging material, said containers having a moulded opening device.
One object is to manufacture a packaging material suitable for producing packaging containers for liquid and semi-liquid food wherein the packaging container has a moulded opening device having a high efficiency in regard of the amount of material used and the time needed for production of the opening device.
The above and other objects are achieved by a packaging material for a packaging container for liquid or semi-liquid food, comprising a bulk layer, which on one side has a heat-sealing layer, and wherein the packaging material comprises one or more weakening(s) in direct or indirect contact with an attenuation or a hole in the packaging material.
The above and other objects are achieved by a method of manufacturing a packaging container by providing a packaging material as described herein, arranging, on one side of the packaging material, a first mould portion comprising at least a first mould cavity, arranging a second mould portion comprising at least a second mould cavity on the opposite side of the first mould portion and on the opposite side of the packaging material, wherein the first mould cavity at least partly overlaps the second mould cavity, injecting a plastic melt into at least one of the mould cavities, allowing the plastic melt to come through the packaging material in an overlapping area in order to form a material bridge, allowing the plastic melt to flow into at least the opposite mould cavity and subsequently removing the first and the second mould portions, obtaining a packaging material comprising an opening device, forming the packaging material comprising the opening device to a desired shape, filling and sealing the formed packaging material with a liquid or semi-liquid food product, and obtaining a packaging container having an opening device.
The above and other objects are achieved by a packaging container comprising a packaging material laminate and a plastic opening device and a consumer opening area and wherein the plastic opening device comprises a first portion on the outside of the packaging container connected via a material bridge to a second portion on the inside of the packaging container, the packaging material laminate extending within the consumer opening area such that it is ruptured on using the opening device to open the consumer opening area.